Secure Communication using Identity Based Encryption

Secured communication has been widely deployed to guarantee confidentiality and\ud integrity of connections over untrusted networks, e.g., the Internet. Although\ud secure connections are designed to prevent attacks on the connection, they hide\ud attacks inside the channel from being analyzed by Intrusion Detection Systems\ud (IDS). Furthermore, secure connections require a certain key exchange at the\ud initialization phase, which is prone to Man-In-The-Middle (MITM) attacks. In this paper, we present a new method to secure connection which enables Intrusion Detection and overcomes the problem of MITM attacks. We propose to apply Identity Based Encryption (IBE) to secure a communication channel. The key escrow property of IBE is used to recover the decryption key, decrypt network traffic on the fly, and scan for malicious content. As the public key can be generated based on the identity of the connected server and its exchange is not necessary, MITM attacks are not easy to be carried out any more. A prototype of a modified TLS scheme is implemented and proved with a simple client-server application. Based on this prototype, a new IDS sensor is developed to be capable of identifying IBE encrypted secure traffic on the fly. A deployment architecture of the IBE sensor in a company network is proposed. Finally, we show the applicability by a practical experiment and some preliminary performance measurements

Coding theory and discrete transforms

We investigate a new approach to the construction of linear block codes, the so-called loop transversal approach. First, we use a greedy algorithm to construct syndrome functions of binary lexicodes up to high channel lengths, presenting tables of dimensions for these codes. The graphs of the syndrome functions turn out to have curious fractal properties. In order to investigate these functions, we then consider them as polynomials in subfields of the quadratic closure of GF(2). Passing from such a polynomial function to its coefficient sequence provides a linear transform, analogous to the discrete Fourier transform. Although the matrices of the transforms are non-sparse and increase exponentially in size, we are still able to invert them explicitly. The inverse transform matrices again have a fractal structure, including the Sierpinski triangle in their first row. The transforms of the syndrome functions are exhibited. Two features of these transforms are readily apparent. The first is the apparent simplicity of the transforms when compared with the original syndromes. The second is the similarity of the transforms for the various syndromes. This similarity illustrates the way in which the syndrome functions generalize the logarithm function;Secondly, we use the transform to analyze certain spaces of natural number functions that include the syndromes of the codes. Transforms of functions in these spaces exhibit a martingale property;Finally, we present an alternative, more elementary approach (compared with (Le2)) to the solution of a problem posed by J. H. Conway on exponentiation in the quadratic closure of GF(2)

Dynamic dissipative cooling of a mechanical oscillator in strong-coupling optomechanics

Cooling of mesoscopic mechanical resonators represents a primary concern in cavity optomechanics. Here in the strong optomechanical coupling regime, we propose to dynamically control the cavity dissipation, which is able to significantly accelerate the cooling process while strongly suppressing the heating noise. Furthermore, the dynamic control is capable of overcoming quantum backaction and reducing the cooling limit by several orders of magnitude. The dynamic dissipation control provides new insights for tailoring the optomechanical interaction and offers the prospect of exploring macroscopic quantum physics.Comment: accepetd in Physical Review Letter

2-[3-(1H-Benzimidazol-2-yl)prop­yl]-1H-benzimidazol-3-ium 3,5-dicarb­oxy­benzoate–benzene-1,3,5-tricarb­oxy­lic acid–water (1/1/1)

The title compound, C17H17N4 +·C9H5O6 −·C9H6O6·H2O, contains a protonated 2,2′-(1,3-propanedi­yl)bis­(1H-benzimidazole) cation, a deprotonated benzene-1,3,5-tricarb­oxy­lic acid anion, a neutral benzene-1,3,5-tricarb­oxy­lic acid mol­ecule and a water mol­ecule, which are linked together through N—H⋯O, O—H⋯O and weak C—H⋯O hydrogen bonds into almost double sheets parallel to (4 ). These hydrogen-bonded sheets are packed in the crystal with the formation of centrosymmetric voids of 25.5 Å3, which are filled by the water mol­ecules

Development of a reaction cell for in-situ/operando studies of surface of a catalyst under a reaction condition and during catalysis

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Review of Scientific Instruments and may be found at https://aip.scitation.org/doi/10.1063/1.4946877.Tracking surface chemistry of a catalyst during catalysis is significant for fundamental understanding of catalytic performance of the catalyst since it allows for establishing an intrinsic correlation between surface chemistry of a catalyst at its working status and its corresponding catalytic performance. Ambient pressure X-ray photoelectron spectroscopy can be used for in-situ studies of surfaces of different materials or devices in a gas. To simulate the gaseous environment of a catalyst in a fixed-bed a flowing gaseous environment of reactants around the catalyst is necessary. Here, we report the development of a new flowing reaction cell for simulating in-situ study of a catalyst surface under a reaction condition in gas of one reactant or during catalysis in a mixture of reactants of a catalytic reaction. The homemade reaction cell is installed in a high vacuum (HV) or ultrahigh vacuum (UHV) environment of a chamber. The flowing gas in the reaction cell is separated from the HV or UHV environment through well sealings at three interfaces between the reaction cell and X-ray window, sample door and aperture of front cone of an energy analyzer. Catalyst in the cell is heated through infrared laser beam introduced through a fiber optics interfaced with the reaction cell through a homemade feedthrough. The highly localized heating on the sample holder and Au-passivated internal surface of the reaction cell effectively minimizes any unwanted reactions potentially catalyzed by the reaction cell. The incorporated laser heating allows a fast heating and a high thermal stability of the sample at a high temperature. With this cell, a catalyst at 800 °C in a flowing gas can be tracked readily

Linear and nonlinear properties of photonic band-gap fibres

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Design of a new reactor-like high temperature near ambient pressure scanning tunneling microscope for catalysis studies

This is the published version. ©Copyright 2013 American Institute of PhysicsHere, we present the design of a new reactor-like high-temperature near ambient pressure scanning tunneling microscope (HT-NAP-STM) for catalysis studies. This HT-NAP-STM was designed for exploration of structures of catalyst surfaces at atomic scale during catalysis or under reaction conditions. In this HT-NAP-STM, the minimized reactor with a volume of reactant gases of ∼10 ml is thermally isolated from the STM room through a shielding dome installed between the reactor and STM room. An aperture on the dome was made to allow tip to approach to or retract from a catalyst surface in the reactor. This dome minimizes thermal diffusion from hot gas of the reactor to the STM room and thus remains STM head at a constant temperature near to room temperature, allowing observation of surface structures at atomic scale under reaction conditions or during catalysis with minimized thermal drift. The integrated quadrupole mass spectrometer can simultaneously measure products during visualization of surface structure of a catalyst. This synergy allows building an intrinsic correlation between surface structure and its catalytic performance. This correlation offers important insights for understanding of catalysis. Tests were done on graphite in ambient environment, Pt(111) in CO, graphene on Ru(0001) in UHV at high temperature and gaseous environment at high temperature. Atom-resolved surface structure of graphene on Ru(0001) at 500 K in a gaseous environment of 25 Torr was identified